Signors



(No Maelb) 2 sheets-sheet 2.

E. H.'& A. H. GOWLES. PROCESS 0E SMELTINC oEEs BY TEE ELECTRIC CURRENT.

No. 319,795. Patented'JuneC, 1885.

PVITJVESAS'ES @Ntra 'ra-iras rivier.

'EUGENE H. COWLES VAND ALFRED l-l.

SlGNRS, BY DIRECT A ND MESNE coWLEs, o F CLEVELAND, omo, AsassIcNMENTs, or FOUR-'ramas' To Paocsss oF smart/ING ones BY THE ELECTRIC CURRENT.

srncrmcnnon forming aa of Letters Patent No. 319,795, dated June e, isses.

Applicants 'ned December 24, '1884. ca maan To allwhom it may concerne Be it .known that we, EUGENE H. CowLEs and ALFRED H. COWLES, citizens ofthe United States, residing at Cleveland, in the' count-y of Cuyahoga'and State of,Ohio,have invented certain new and useful lmprovementsin Processes for Smelt-ing Ores bythe Electric Current; and we dohereby declare the following to be a"full,clear,and exact description of the 1 o invention, suclh as will enableV others skilled in the. art' to which it appertains to make and use the same, reference being had to the accompanying drawings,- and to letters or figures of reference marked thereon, which form a part of this specifcation.

The present invention relates to the class of -fsmelt-ing-furnaees whichl employ an electric current solely as a source of heat..v Heretofore it has been' attempted to reduce ores and perzo form metallurgical operations by means of an electric arc, vthe material to be treated being brought within the'field .of the arc or passed or fed through-it; but numerous experiments havedemonstrated that the are system is not 2 5 adapted for l'on g andcontinuousoperations on a scale of any considerable magnitude. The dieulties attending the regulation of the arc and the preservation of a constant resistance are very great, and the heatgenerated, though 3o intense, is localized and difficult to control. The object of this invention is to provide a process by which electricity can be practically employed for metallurgical operations, and for this purposcto secure a distribution. of the intense-heat which it is well known electricity is capable of generating over a large area' or through a large mass'in' such-a manner that a high temperature can be sustained for 'a long time and controlled.

4o To this end t-he invention consists, essentially, in the use for metallurgical'purposes of aoody of granular material of high resistance er-low conductivity interposed within the circuit in such n mari-ner aste form a con tinuous and unbroken part of thesame, which granulail body by reason of itsresistauec lsmade incandescent. and generates all the heatre quired. The ore or light material to be re'- duced-as, for example, the hydrated oxide of- 5o aluminium,alum, chloride of sodium,oxde of calcium, or sulphate of stroutiumis usually mixed with the body of granular resistance material, and is thus brought directly in contact with the heat at the points ot generation at thesamc time lheheatisdistributedthrough v5 5 themass ot' granular material, beinggenerated by the resistance of all the granules, and is not localized at one point or along a single line. The material' best adapted forthis purpose is electric-light carbon, asit possesses the necessary amount of electrical resistance, and is capable of 'enduring any known degree of heat vwhen 'protected from oxygen without disintegrating or fusing;l but crystalline silicon or other equivalent of carbon can be employed for the same purpose. This is pulverized or granulated, the degree ot granulation depend- 4iu'g upon the size of the furnacev Coarse granul lated carbon works better than finely-pulverized carbon and gives more even results. They 7o electrical energy is .more evenly distribute and the current cannot so readily forma path of highest temperature and consequently of least resistance'th rough the massalong'which the entire current or the bulk of the current can pass;'but the scope of this invention is not limited by the degree of granulatiou, as' that may vary with the conditions of the case, and with a large furnace and a powerful cur-v rent the size of the carbon particles may pass beyond what is ordinarily understood by the term granular and be, in fact, pieces of car- Abon of considerable size. Still the resistance body is ordinarily composed of grains or. pieces proximately equal in size, in'order to secure an even distribution of the electrical energy.

The operation .must necessarily be conducted within 'an air-tight chamber or in a nonoxidizing atmosphere, as other-wise the earbon will be consumed and actas fuel. The carbon acts as a deoxidizing agent for the ore or. metallifcrous material treated, and to. this extentit consumed, but otherwise than [rom this cause it remains uuimpaired.

We `will illustrate and describe a zinc-fui nace cmbm'lyingour invention, from which the application of thc sameto thc reduction or smelting of other kiuds"`of ores' willbe;

readily understood, especially of, aluminium,

silicium,magnesium, boron, and other rare :co-

' and Fig. 2 is a front view of` the same',

This retort consist-s of a cylinder, made of silica-or other non conducting material, suitably embedded inv a body, B, of powdered charcoal, mineral wool, or of some other Inaterial which is nota good conductor of heat.

' 'lh'c rear end of the retort-cylinder is closed bymea-ns of a carbon-plate, C, which plate forms the positive' electrode, and with this plate the positive wire of the electriccircuit is connected. The outer end of the/retort is closed by mea-ns of lin-inverted graphitc-cru cible, D, to which the negative wire of the electric'circuit is attached.v This graphite crucible serves as n plug for closing vthe end lof the retort. It also forms a condensing chamber for the zinc-fumes, and it also constitutes the negative electa-mic.v The term electrode 'is used in this case as designating the terminals of the circuit proper, or that portion of it which actsjsimply as an electrical conductor, and not with thejntention of indicating'thc ends of a line between which there is no circuitconnection. The circuit between t-he electrodes, so called, iscont-inuous, being established by means of and through'the body ot' broken carbon.- The mouth of the cruc'ible is closed with aluting of clay or otherwise, and the openina` d, made in the upper side of the Crucible, near its cx-V tremily, comcsentirely within the retort and forms a passage for thezinefnmes from the retort-chamber into the condellsingjchamber, i

The pipe E serves as a vent'for the-condensing-chamber.4 The zinc ore is mixed with the pulverized or granular carbon and the -retort charged nearly full throu h the front end with the mixtpre, the plug. beingremovedl for this purpose.. A small space is left at the top, as shown. -After the plughas'been inserted and the joint properly lu'ted the electric circuit is closed -and the current allowed to pass through the retort,

. traversing its entire lcngththrough the body of mixed ore andcarbon. The carbon constituents of the mass become incandescent, generating: a very high degree of heat, and being-in direct contact with the ore -the lat` ter is rapidly and'eifectually reduced and disiillcd.

, The lit-at evolved distills the zinc, and the xbm-fumes are condensed in the condensingchamber precisely as in the present method ot' zinc-making, with this important exception, that aside from `the reaction produced by heating carbon in the presence vof zinc oxide th'eclcctric current in passing through the zincoxidehas a decomposing and disintegrat-ing` action upon it, not unlike theeffect produced by an electric current inasolution. This action accelerates the distillation and promotes economy in the process.

ture of incandescent carbon and ore adords the most effective utiliza-tion of 'all the lleat through anyintcrvcliing bodies or spaces.

Moreover, themaximum degree of heat geuerated bythe furnace is within 'the 'orc body', and the retort and furnace receive only the ore and carbon cpntainedwithi n consequently the retort or the furnace is not'subjected to .the highest degree of heat, as is thecase in the BelgianI method 'of zinc-smelting, and 'the life-time of n retort is thus materially increased. It is proposed to use a number of these retorts in the saine circuit, in series or multiple are, as desired? l le havefound in practice that a mixture half partey of zine ore, bv weight, gives most satisfactory results wit the particular ore which we haw treated; but. the roportions to be used will depend u the ore and the degree o heat required to re-4 duce it, and the degree of heat evolved willbe determined by the resistance or conductivity It will be observed that theintimate lnixi 7o evolved. vNone of itvis lost by transmission heat which is transmitted outward `from the f n thee iaracter of 9o of the mass and the'strengthof the current ciuy ployed;

Fig, 3 illustrates animprovcd form of furnace operating in the same manner as the one just described..

'lhe furnace or retort clmmbcrF has au inclined iloor` sloping from both ends down toa discharge-hole,f, through which the metal and slag or residue can be withdrawm G G' are thc electlrmie-plates forming the ends ot' tha fumace-chamber,conuected,respectively,with .the electric wires. HI is the condenser,'and I I I are hoppers for charging'the furnace, se"- eral being provided, to distribute the charge evenly along the chamber. The hoppen I and the 'dischargeopening f are closed lwith lire-clay plugs. This furnace admits of the use of heavy walls and solid' permanent conregulation of the resistance of 'the charge is secured by means of the several feed-hoppers, an additional amount being fed in when resistbeing withdrawn through thc bottom when the resistance is too low.

In the reduction of an orc composedof n non. volatile metal, ora metal which is not volatilized at'the heat generated in the furnace, the metal remains in the furnace mixed with the carbon filling the interstices between tho grains,.while the gases produced pasa oflj'. In the reduction of raro metals, where n pure product is desired, it is necessary to use a lpure carbon, or a carbon free from iron or other foreignv ingredient, otherwise the iron or other substance will go into the product.

fe do not in t-hisapplicatiou make any claim to the furnace or apparatus herein deiscribed, as that is ireserved for the subject mutter of a separate application; and we are aware that an electric current. has been em-l struction, and also a prolonged heat. l A nice 8s of about one4 part 'of carbon-with one and a ris'. ance is too high, and a portion of 'the charge Y ployed in the reduction of fused ores, and we do not clain thc same, broadly; but

What Wc do claim as' ouuinvention, and dcsire to secure by Letters Patent, is- Y l. The method of generating heat for metallurgical operations herein described, which' uniss, and the operation can be performed solely by means of electrical energy.

2. fhemethod of smelting or reducing ores or lnetalliferous compounds herein described, which consists in subjecting the 'ore in the presence'of carbon to the action of heat generated by passing an electric cu rrent through u body of broken orpulverized resistance ma'- 'terial that forms a continuous part of the electric circuit, the ore being in contact with thc broken or pnlverized resistance material, whereby the ore isreduced by the combined action of the carbon and of the heat generated solely by the resistance of 4the broken or pnlverized body throughout its massA 3. The method of smelting or reducing ores or metalliferous compounds herein described,

which consists in pulverizing the ore and mix-A ing with it pnlverized or 4broken carbon or like material, then introdncinv the mixed ore and carbon within an electric circuit, of which it forms acont-inuons part, the said circuit being established through the carbon constituents of the mass, whereby the heatis generated by the electrical resistance ofthe carbon throughoutthe mass, and the operationl can be performed entirel y' by means of the carbon reagent `and the electrical energy.

4. The method of smelting or reducing ores or metalliferous compounds herein described, which consists in subjecting the ore in the presence of a reducing agent to the action of heatgeneratedby passing an electric current through a body of broken or pulverized resist-ance material that forms a continuous part of the'electric circuit, the ore beingincontact with the broken or pulverized resistance material, whereby the ore is reduced by the combined action ofthe reducing agent and of the heat generated solely by the resistance of the broken or puberized body throughout .its

mass..

In testimony whereof we affix. our signatures in presence of two witnesses.

` "Witnesses:

J oHN C. CovnR'r, C. A. WHITNEY. 

